1. Field of the Invention
This invention relates to a heat-resisting plate having a cooling structure that is employed in various types of beam devices for handling high-temperature plasma or high-energy particles, and to a method of manufacturing the heat resisting cooling plate.
2. Discussion of the Background
Examples of beam devices that handle high-temperature plasma or high-energy particles are fusion reactors or accelerators. In all such beam devices, the interior of the structural member that handles the high temperature plasma or high energy particles is exposed to extremely high temperature. A heat-resisting plate having a cooling structure is therefore employed for structural members handling such high temperature plasma or high energy particles.
A heat-resisting plate having a cooling structure may be of the type wherein the body of the heat-resisting plate is cooled by passing cooling water through cooling pipes which are mounted by brazing to the body of the heat-resisting plate, or the type wherein the body of the heat-resisting plate is cooled by passing cooling water through passages for flow of cooling water formed in the body of the heat-resisting plate.
However, a heat-resisting plate with cooling pipes mounted on it is subject to the following inconveniences. Specifically, it is difficult to mount the cooling pipes onto the heat-resisting plate body by brazing, and cracks appear in the vicinity of the mounting joint interface. This is due to the difference in the materials of the heat-resisting plate body and of the cooling pipes. Typically, the high melting point metals tungsten W or molybdenum Mo are employed for the material of the heat-resisting plate body, while stainless steel is used for the material of the cooling pipes. However, cooling pipes made of stainless steel melt when fixed securely by brazing to W or Mo plate bodies. Brazing therefore has to be performed at a temperature such that the stainless steel cooling pipes are not melted. A further problem is the occurrence of cracks in the vicinity of the brazed joint interface due to the different linear expansion coefficients of the material of the cooling pipes and the material of the heat-resisting plate body.
On the other hand, in the case of a heat-resisting plate bored with passages to allow the flow of cooling water in the heat-resisting plate body, the material of the passages and the material of the heat-resisting plate body is the same However, since tungsten W or molybdenum Mo is employed as the material of the heat-resisting plate body, there are problems regarding corrosion resistance to the cooling water.